Generally better to use the fins in matched sets (by flex). While the softer flex style fins are working well in wave riding mode; when pushed to the limit you ideally want fins that all flex in a co-ordinated manner,,,
You may find the less flexy G10 better when pushing a board like Quad into B+J mode, where "blasting" across chop to get up speed to get the chop hops is more the target, compared to having soft flexy fins staying hooked up and tracking during wave riding.